There should be pins where you would normally hook up USB drives, they should look like the exact opposite of the connector. Try tracing the USB ports from the case to the MOBO. You should have bought one with a PCI Connection, its much better.
Its fire wire not USB. If the bracket came with the motherboard there will be a place to plug it in. There's absolutely no reason to tell someone a pci one is better if the board has a fire wire header, its not. That's a direct plugin to the fire wire controller on the board